1. Technical Field
The present invention relates to turbo machines and refrigerating cycling apparatuses.
2. Description of the Related Art
Hitherto, refrigerating machines that include a turbo machine are known. The turbo machine is used as a compressor that compresses a refrigerating gas evaporated by an evaporator so as to be sent to a condenser.
As illustrated in FIG. 8, for example, JAPANESE UNEXAMINED PATENT APPLICATION PUBLICATION NO. 2010-31698 describes a refrigerating machine 300 including a compressor 301, an evaporator 302, a condenser 304, a cooling water tower 316, and a cooling water pump 318. The refrigerating machine 300 uses water as a refrigerant. The compressor 301 includes a rotation shaft 310, an impeller 312, and a bearing 320. In the compressor 301, water as a lubricant is supplied to the bearing 320. Specifically, a portion of cooling water to be supplied to the condenser 304 is sent to the bearing 320 by using the discharge pressure of the cooling water pump 318.
FIG. 9 is a partial magnified view schematically illustrating a structure of a bearing 320 and a section including a sealing portion 330, which separates a space in which the bearing 320 is disposed from a compressing chamber 323, of the compressor 301 illustrated in FIG. 8. The sealing portion 330 in a housing 322 separates the space in which the bearing 320 is disposed from the compressing chamber 323, and is fixed to an inner surface of the housing 322 at a position between the compressing chamber 323 and the bearing 320, which is adjacent to the compressing chamber 323. The sealing portion 330 is a ring-shaped non-contact type seal and is fitted to an outer surface of a rotation shaft 310 with a gap. The compressing chamber 323 is maintained at a negative pressure with respect to the space in which the bearing 320 is disposed, and thus some of the lubricant in the space in which the bearing 320 is disposed is drawn toward the compressing chamber 323 through a space between the sealing portion 330 and the rotation shaft 310. At this time, the sealing portion 330 prevents a large amount of lubricant water from being rapidly sucked into the compressing chamber 323.